The present invention relates to a pipe bending machine of the type having an elongated supporting frame defining two opposite longitudinal sides and a head face, a feeding carriage movable along an upper edge of one longitudinal side of the frame, a collet mounted on the carriage for holding a pipe, a bending table arranged at the head face of the supporting frame to turn about an upright axis of rotation, a bending die secured on the bending table, a clamping jaw and a slide bar arranged in the range of the one longitudinal side of the frame to cooperate respectively with the bending dye.
As known, bending machines of the aforedescribed kind are employed for cold bending of pipes. During this process, a bending core bar can be additionally inserted in the interior of the pipe to be processed.
Bending machines of this construction are suitable particularly for bending pipes of larger diameter which are subject to multiple bending at large bending diameters. In this mode of operation, the bending freedom required from the bending machines is not of particular significance, since in contemporary digitally controlled pipe bending machines the bending freedom that means the precaution that the parts of the pipe do not hit a component part of the machine during the bending process is tested and incorporated in the control program. Pipes of smaller diameter though are bent at smaller bending radii. As a consequence, during the bending operation the danger is present that the bent part of the pipe might strike on the machine. Accordingly, the question of bending freedom in the latter case is of large importance.